Depressed or anxious persons may show a negative bias in cognitive evaluation. Because this effect is observed in normal as well as pathological mood states, it may reflect the operation of adaptive mechanisms: the emotional systems of the brain seem to monitor pleasures and threats, and to alter cognitive evaluation accordingly. This proposal attempts to characterize the operation of emotional control systems on several levels, drawing from current neuropsychological models of arousal, emotion, and temperament. By studying university students who score high or low on measures of depression or anxiety, it may be possible to examine normal analogs of emotional disorders. By experimentally inducing depressed or anxious states in unselected students, the influence of current emotion state may be separated from trait factors. For both approaches, the hypothesis is that there are two dimensions of neural arousal which are experienced subjectively as depression-elation and relaxation-anxiety. Psychometric analyses examine the extent to which these dimensions describe both self-reported emotional state and psyiological arousal and reactivity. A cognitive priming paradigm tests the prediction that greater elation primes representations of pleasures whereas greater anxiety primes representations of threats. Electrophysiological recordings assess neural activity that may be sensitive to the cognitive priming effects, and spectral analysis of the background EEG examines frontal lobe activity that may be relevant to emotional control mechanisms. By coordinating measurements on these several levels, it may be possible to characterize mechanisms through which neural arousal, emotional state, and cognitive appraisal are regulated simultaneously as integrated components of the brain's emotional control system.